$\"\"$

The function is $\"\"$ and the point is $\"\"$ .

$\"\"$ .

Apply derivative on each side with respect to $\"\"$ .

$\"\"$

Derivative of the cosine function: $\"\"$ .

$\"\"$

$\"\"$ .

Slope of the tangent is derivative of the function at given point.

Find the derivative at $\"\"$ .

$\"\"$

Slope of the tangent line is $\"\"$ .

$\"\"$

Point - slope form of line equation is $\"\"$ .

Substitute the values $\"\"$ and $\"\"$ in above formula.

$\"\"$

The tangent line equation is $\"\"$